Premium liquid-applied polyurethane systems for metal, corrugated, and profile roofs. Standard waterproofing and LEED-compliant cool roof options. Zero operational downtime. Written 10-year guarantee.
Both systems begin with the same rigorous preparation and joint treatment. The cool roof system adds a UV-reflective white topcoat that qualifies for LEED SS Credit 7.2 and significantly reduces building heat gain.
The foundation of every long-lasting waterproofing system. All dust, dirt, grease, loose paint, rust scale, and contaminants are completely removed from the metal substrate. Mechanical cleaning of rusted areas using wire brush, angle grinder, or abrasive paper as required. The roof must be completely dry before any material is applied — application over damp metal causes adhesion failure and is prohibited under system specification.
All corroded metal areas are treated with an anti-rust primer specifically formulated for metal substrates. The rust converter chemically neutralises active corrosion and converts iron oxide to a stable compound that bonds to the metal surface. Applied immediately after mechanical preparation and before any moisture can re-form on the cleaned metal. Curing time strictly observed as per manufacturer’s data sheet before any subsequent coat is applied.
Metal roofs leak at their seams and fasteners — not through the metal itself. This step addresses every potential failure point systematically before the main membrane is applied. All side laps, end laps, rivets, self-drilling screws, penetrations, flashings, gutters, and skylight junctions are individually treated. This is the most labour-intensive and most critical step in the system.
An approved polyurethane primer specifically formulated for metal substrates is applied across the full roof surface. The primer promotes adhesion between the metal and the waterproofing membrane, penetrates micro-pores in the surface, and prevents osmotic blistering. Coverage and application method strictly per manufacturer’s technical data sheet. Surface temperature must be at least 3°C above dew point during application.
The first coat of liquid-applied polyurethane waterproofing membrane is applied to the full primed surface. This coat establishes the initial waterproof barrier and provides the base for the reinforcement layer and second coat. Applied by brush, roller, or airless spray at the specified coverage rate. Film thickness checked by wet film gauge during application.
Polyester fleece or polyamide reinforcement mesh is embedded into the wet first coat at all critical movement and stress areas. The reinforcement bridges structural movement, resists cracking at high-stress junctions, and provides additional puncture resistance. This layer is applied after the first coat is applied but while still wet (tacky) to ensure full embedment.
The second and final coat of polyurethane membrane is applied perpendicular to the first coat. Applying the second coat at 90° to the first eliminates pin-holes and ensures uniform dry film thickness across the entire surface. The total dry film thickness of the completed two-coat system meets or exceeds the specification requirement. Film thickness is verified by measurement before the coating is accepted.
Complete removal of all dust, dirt, grease, loose paint, rust scale, and contaminants from the metal substrate. Mechanical cleaning of all rusted areas using wire brush, angle grinder, or abrasive paper. Roof must be completely dry before any material is applied. A clean, profiled surface is the non-negotiable foundation of a durable cool roof system.
SSPC-SP3 · Moisture-free substrate requiredAnti-rust primer applied to all corroded metal areas immediately after mechanical preparation. Curing strictly observed per manufacturer’s data sheet. Two coats applied to severely corroded areas. Full cure verified before any subsequent application. Rust that is not chemically arrested will continue to spread beneath the membrane system, causing premature failure.
Phosphoric acid converter · 4–8 hr cure at 30°CAll side laps, end laps, rivets, self-drilling screws, penetrations, flashings, gutters, and skylight junctions are individually sealed with polyurethane sealant and reinforced with polyester fleece or polyamide mesh embedded into wet membrane. This systematic joint treatment is identical in the cool roof system — the reflective performance of a cool roof coating is worthless if the membrane below leaks at the seams.
Polyamide 120 g/m² · All laps, penetrations & junctionsApproved polyurethane primer applied to the full roof surface at coverage per manufacturer’s specifications. The primer creates the chemical bond between the metal substrate and the waterproofing membrane above it. Surface temperature must be at least 3°C above dew point. Application method and cure time per technical data sheet.
PU primer for metal · 0.15–0.25 kg/m²First coat of liquid-applied polyurethane waterproofing membrane applied to the full primed surface at approximately 0.75–1.0 kg/m². Film thickness verified by wet film gauge. Particular attention to profiled areas, valleys, and all geometric transitions. Minimum cure time observed before application of reinforcement and second coat.
0.75–1.0 kg/m² · Wet film gauge verificationPolyamide or polyester fleece reinforcement embedded into the wet first coat at all high-movement and high-stress areas: side laps, end laps, skylight joints, gutter joints, expansion joints, pipe penetrations, and all repaired areas. Full embedment is required — no dry spots, bridging, or voids in the reinforcement layer.
Polyamide 120 g/m² · Full wet embedmentSecond coat applied perpendicular to the first coat to eliminate pin-holes and ensure uniform dry film thickness. Total DFT: 1.2–1.5 mm for standard exposure; 2.0 mm+ for heavy-duty exposure. This provides the complete waterproofing barrier before the cool roof topcoat is applied above it.
DFT 1.2–1.5 mm standard · 2.0 mm+ heavy dutyA white, UV-resistant aliphatic polyurethane topcoat is applied over the cured waterproofing membrane. This is the defining layer of the cool roof system. The highly reflective white surface reflects the majority of incident solar radiation rather than absorbing it, dramatically reducing roof surface temperatures and the heat conducted into the building below.
Every metal roof waterproofing system we complete is backed by a written guarantee of up to 10 years. The document specifies the materials used, the system applied, the covered failure modes, and the remedy procedure. Issued on the day the work is signed off — before you make final payment.
💬 Get a Free QuoteOur specialist visits your warehouse or factory, assesses the full roof condition, and provides a written quote specifying every material, every square metre, and the exact system to be applied. No guesswork. No hidden costs.